• Archives of Plastic Surgery
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• 제35권2호
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• pp.219-222
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• 2008

Purpose: The purpose of this study is to develop hydroxyapatite cement simplified procedures for reconstruction of craniofacial deformities. Due to its expense and characteristics of quick hardening time, it may be inappropriate for forehead reconstruction or augmentation. Therefore we hear by introduce a more precise, easy and cheap method. The authors report forehead reconstruction with hydroxyapatite cement for a patient who suffered from craniofacial deformity. Methods: Case report and literature review. Results: A 35 year old man came to us with forehead and temporal area depression. He had a history of brain operations due to traumatic epidural hematoma. A physical exam showed an evidence of right side forehead weakness sign. Authors made RP model of his skull and applied check framework with Kirschner's wires for measuring accurate volume and contour on the depressed right side forehead area on the RP model. After complete exposure of defect area by bicoronary insicion, absorbable plate which applied on skull area was removed. Using three Kirschner's wires, authors made check framework on the right forehead lively and fixed with 2-hole miniplates on the boundary of the defect. After checking asymmetry, hydroxyapatite was applied on check shape framework just above Kirschner's wire. After removing Kirschner's wire, we corrected minimal unbalance and contour with bur. Conclusion: Check framework with Kirschner's wire was very convenient and cost saving methods for forehead reconstruction with hydroxyapatite cement.

• 구강회복응용과학지
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• 제22권1호
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• pp.11-21
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• 2006

The adjustable dental impression trays were made for being adjusted their width automatically along the width of patient's dental arch. The purpose of this study was to investigate the retentive force of adjustable dental impression trays made of different synthetic resin materials. Three pairs of adjustable trays were made of ABS(acrylonitrile butadiene styrene) synthetic resin, polyurethane synthetic resin and polycarbonate synthetic resin with a hole and without a rim on the border area of them. The experiment was done with the horse-shoe shaped metal plate to pull out the set impression body from the tray jig which was made for holding the tray on the lower part of Universal Testing Machine(UTM, Zwick Z020, Zwick Co., Germany). After the alginate impression in the tray was allowed to set four minutes, a tensile force was applied at right angles to the tray which had been previously seated on the jig. The force was applied to measure a maximum force by use of UTM at a constant strain rate 100mm per minute. The results obtained in this study were as follows : 1. The upper trays were showed higher retentive force than lower trays in three tray materials. 2. There was no significant difference in the retentive force of the tray materials(p>0.05).

• 융합신호처리학회논문지
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• 제20권4호
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• pp.199-204
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• 2019

경계층 내 측정된 유속은 변동 성분을 활용한 표준편차 혹은 배경 유속을 포함한 평균 속도로 해석되어 왔다. 하지만, 각각의 결과로 유동 상호작용을 설명하는데 한계가 있어 본 논문에서는 시간 영역의 유속을 퓨리에 변환하여 주파수 분석으로 유동 현상을 규명하는 방법을 제안한다. 이를 위해 경계층 내 평판 위에 부착된 반구 내부로 염료를 주입시켜 후류 영역에서 생성되는 머리핀 와류를 가시화하여 발생 빈도를 계측하였다. 또한 반구 전방의 평판을 뚫어 흡입함으로써 후류 영역 내 유속 변화를 열선 유속계로 측정하였다. 제안된 주파수 분석의 평가를 위해 기존의 통계 해석법과 비교하였으며, 유동의 정성적인 결과에 부합하는 주파수 분석과정을 제시한다.

• 한국광학회지
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• 제17권3호
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• pp.273-277
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• 2006

홀버닝 광메모리의 광원으로서 상용 반도체 레이저 다이오드에 Littman형 및 고정방향 Littrow형 외부공진기를 결합하여 파장가변 레이저 다이오드 시스템을 제작하고 성능을 비교 분석하였다. 두 형태의 파장가변 레이저 다이오드 시스템 모두 0차 출력광은 단일종모드로 동작하며 CFP(Confocal Fabry-Perot)의 분해능인 9MHz이내의 선폭을 예상할 수 있었으며 다이오드 구동전류 140mA 및 동작 온도 $25^{\circ}C$의 조건하에서 거울 및 회절격자를 수동나사로 회전시키는 성긴 튜닝시 Littman형은 5.375nm, 고정방향 Littrow형은 13.65 nm이상의 파장가변 범위를 보였고 PZT (Piezoelectric Transducer)에 200Hz의 톱니파 전압을 인가해서 거울을 회전시키는 미세 튜닝 시 두 형태 모두 0.042nm의 범위 내에서 연속적인 파장가변이 가능하였다. 특히 고정방향 Littrow형 외부공진기는 출력광의 방향이 바뀌는 기존의 단점을 보강하였으며, 또한 외부공진기의 길이에 따른 최대파장가변 범위를 측정하였다.

• 박물관보존과학
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• 제7권
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• pp.25-31
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• 2006

경남 창녕군 화왕산성에서 발굴된 비격진천뢰의 보존처리를 실시하였다. 비격진천뢰는 일부 결실된 상태였다. 단, 결실된 부분은 내부를 관찰할 수 있도록 복원처리를 실시하지 않았다. X-선 투과검사 및 C.T(Computed Tomography)촬영 결과 주조과정에서 주형선 주위에 기공이 많이 발생한 것을 확인할 수 있었고, 표면에는 주조시 내범을 유지하기 위한 형지공이 확인되었으며, 이 부분에 다시 철판을 덧대어 보강한 흔적도 확인할 수 있었다. 표면에 존재하는 청색 부식물의 주성분은 SEM/EDS 분석결과 산소(O), 철(Fe), 인(P), 규소(Si), 알루미늄(Al)이라는 것을 확인하였으며, XRD 분석결과 청색 부식물은 비비아나이트[vivianite, Fe₃(PO₄)₂·8H₂O]로 확인되었다. 그리고 미세조직 분석결과 전형적인 회주철조직으로 판명되었다.

• 한국운동역학회지
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• 제20권2호
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• pp.239-243
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• 2010

The putting stroke accounts for 40~50% of total stroke for a golf rounding and most golfers have difficulties on the puting. Studies for the putting stroke have been conducted by analyzing various factors such as kinematics, kinetics, psychologic and physiologic parameters. A lot of devices were developed to support the studies. However there was no appropriate method to measure the position of the ball quantitatively. In this study, we developed a new measurement system to measure and evaluate the putting result. The developed system uses a USB camera to take the 2-dimensional image of the surface including the hole cup at the center of the image and the ball. The position of the ball is extracted as a set of distance and angle in polar coordinate system. We evaluated the new system with an indoor set-up for putting experiments and the system provided accurate measurement results. The proposed system can be combined with the other measurement systems such as 3D motion capture system and force plate without any restriction.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제31권2호
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• pp.127-135
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• 2009

Objectives : The titanium fixation system has been used in orthognathic surgery for fixation of bone segments usually, but the biodegradable fixation system was developed and also being used. The strongest point in the biodegradable system is that no extra operation should be needed to remove fixation materials. In spite of this merit, oral & maxillofacial surgeons hesitate to use this system in fracture or orthognathic surgery. In this study, as we got some clinical experiences, we'd like to report the result of clinical study using the biodegradable fixation system in orthognathic surgery. Patients and Methods : A total of 35 patients composed of 17 males and 18 females with 25 osteotomies in maxilla and 34 osteotomies in mandible were fixated with the biodegradable fixation system(Inion $CPS^{(R)}$). We investigated methods of stabilization, fixation time, and complications on the basis of the method as above. Results : Four 2mm thick L shaped plates with 7 holes of which 1 hole was removed were fixed in maxilla with six $2.0{\times}7mm$ screws. Three $2.5{\times}16{\sim}18mm$ screws were used to fix superior ramus area and one mandibular angle area in mandible. It took about 27.4 minutes in maxilla, 25.3 minutes in mandible to perform the fixation which took longer time than the titanium system(9.5 minutes in maxilla, 8 minutes in mandible). Generally, there was no problem except 9 cases in which there were some complications. Conclusions : In most cases, the biodegradable fixation system can be used without problem in usual orthognathic surgery. But, this system is inferior to the titanium fixation one in some respects such as fixation time, size, and physical property. Some supplementations for such weak points as aforementioned should be needed for the universal use of biodegradable materials.

• 한국임상수의학회지
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• 제24권2호
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• pp.276-279
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• 2007

A 2-year-old male, 3 kg body weight Japanese Chin was injured in the automobile accident three months ago. The dog became antebrachiocarpal joint instability, and performed pancarpal arthrodesis using 3 K-wires in localanimal hospital. But, the result was failure. Therefore the dog was referred to Chonbuk Animal Medical Center, Chonbuk National University. In physical examination, right carpal joint instability, knuckling sign and pain were evident. In radiography, sclerosis was observed on the 4th carpal bone. Complete blood count (CBC), serum chemistry and urinalysis finding were within reference ranges. Pancarpal arthrodesis was re-performed using 7-hole plate. However, mild skin and muscle defects was appeared by skin tension of extremity. We expected that granulation would fill the defect, but inflammation was continued on the lesions for 3 days. So, operation which is filling it was done by using the muscle flap and tubed skin flap. The donor muscles were flexor carpi radialis and superficial digital flexor muscles. After 7 days, the muscle flap was survived, but tubed skin flap was necrosed. After 20 days, the skin defect was substituted with granulation tissues. The flexor carpi radialis muscle and superficial digital flexor muscle transposition can be a useful procedure for reconstructing soft tissue defects in the carpal and metacarpal areas.

• 한국정밀공학회지
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• 제18권12호
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• pp.152-158
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• 2001

In this paper, we have developed an electro discharge machine for micro drilling driven by a voice coil actuator. Because the voltage signal of the electro-discharging circuit shows a lot of peaks and valleys, the active type low-pass filtering technique is adopted to get the average of the signal. Since the motion of the voice coil is precisely controlled by the error value between the object voltage value and the measured one, it is possible to prevent the mechanical contact between the rotating electrode and the workpiece and to maintain the appropriate machining conditions during the process. The electro-chemical machining technology was also adopted to make small diameter electrodes. Pure water is used as a dielectric. The machining procedure is performed to verify the feasibility of the developed system. It takes about 10 seconds to drill the ${\phi}m$100${\mu}m$ hole to the 100${\mu}m$ thickness stainless steel plate. The machining time depends on the values of the resister and the capacitor. There may exist the optimal values of time constant and the tendency is displayed In the appendix.

• 한국산학기술학회논문지
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• 제20권4호
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• pp.510-516
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• 2019

본 논문에서는 사용자의 동작을 측정하고 물리적인 변화를 사용자에게 느끼게 하여 실제 스노우보드를 즐기는 것 같은 스노우보드 시뮬레이터를 개발하였다. 스노우보드는 사용자의 무게중심에 따라 속도와 방향이 결정된다. 개발된 시뮬레이터는 스노우보드 플레이트에 4개의 스프링을 장착하여 사용자의 무게 중심의 변화에 따라 기울기를 변화시켜 스노우보드의 기울기 변화를 직접 느낄 수 있게 하였다. 사용자의 무게중심의 변화에 따른 기울기는 3축 가속도센서를 사용하여 측정하였다. 스노우보드의 회전에 따라 발생하는 슬로프의 마찰을 BLDC 모터를 사용하여 사용자가 느낄 수 있도록 하였고, 스노우보드의 회전은 홀센서를 사용하여 측정하였다. 시뮬레이터의 빠른 데이터 처리를 위해 두 개의 MCU를 사용하여 가속도 센서와 모터를 별도로 사용하여 측정된 데이터를 PC로 전송하였다. 개발된 시뮬레이터는 슬로프의 경사 및 마찰을 직접 경험할 수 있으며, 측정된 데이터와 HMD를 착용하여 보다 현실감이 있는 스노우보드를 즐길 수 있도록 하였다.